There are extant various paper sheet collating and sorting machines of the types employing rotary cams to shift or move paper receiving trays between closely spaced relation at opposite sides of a sheet inlet and widely spaced positions for receiving sheets from the sheet inlet.
Such sorting machines are shown, by way of examples, in the following U.S. Pat. Nos.: Stemmle U.S. Pat. No. 3,778,640; Lawrence U.S. Pat. Nos. 4,343,463 and 4,911,424; Sasaki U.S. Pat. No. 5,090,688; DuBois U.S. Pat. No. 4,478,406 and U.S. Pat. No. Maruyama 4,580,775, as well as in the application of P. Coombs filed Mar. 9, 1992, Ser. No. 848,489, co-owned herewith and incorporated herein by reference. The spiral cams of such sorting machines may be machined from solid stock or molded from low friction plastic material. Molding the cams is a difficult and costly procedure due to the fact that the cam profile is most generally formed so that there is a variation in the helix or cam angle, thus requiring a mold of many pieces due to angle differences and resultant mold parting line ridges on the cam profile. On the other hand, rotary removal of a molded cam from a mold is simple in the case that the helix angle is constant by simply unscrewing the cam from the mold.